1. Field Of The Invention
The present invention relates to ultrasonic devices. More specifically, the present invention is directed to an ultrasonic distance measuring apparatus.
2. Description Of The Prior Art
Ultrasonic sensor devices have been developed for measuring the movement of a reflector element as is shown in U.S. Pat. No. 3,140,612. This type of prior art sensor while providing a means for measuring the relative displacement of a movable reflector element fails to provide a mwethod for obtaining the relative separation of the reflector element from the ultrasonic transducer elements whereby a direct measurement of the distance may be obtained. Accordingly, it is desirable to provide an ultrasonic distance measuring sensor for effecting a measurement of the relative separation of a movable reflector element in a direct manner while eliminating the effect of spurious ultrasonic reflections.